Note: When you answer questions involving the test of hypotheses, use the four-step hypothesis process (see textbook pages 298-299).

Also, see your textbook for the full question when necessary; the chapter 9 problems start on p. 303

Chapter 9, problems 4, 12, 14, 22

4.Explain why t distributions tend to be flatter and more spread out than the normal distribution.

12.Last fall, a sample of n = 36 freshmen was selected to participate in a new 4-hour training program designed to improve study skills…: = 74; M = 79.4, s = 18.

a.On the basis of these data, can the college conclude that the students in the new program performed significantly better than the rest of the freshman class? Use a one-tailed test with = .05.

b.Can the college conclude that the students in the new program are significantly different from the rest of the freshman class? Use a two-tailed test with = .05.

14.In the Preview for this chapter, we discussed a study that examined the effect of eye spot patterns on the behavior of moth eating birds: = 30; M = 37, SS = 288, n = 9.

a.Is this sample sufficient to conclude that the eye-spots have a significant influence on the birds’ behavior? Use a two-tailed test with = .05.

b.Compute the estimated Cohen’s d to measure the size of the treatment effect.

22.A researcher would like to examine the effects of humidity on eating behavior. It is known that laboratory rats normally eat an average of = 21 grams of food each day. The researcher selects a random sample of n = 16 rats and places them in a controlled atmosphere room in which the relative humidity is maintained at 90%. The daily food consumption scores for the rats are as follows:

...
Contents
Question 1 3
Question 2a 5
Question 2b 6
Question 2c 7
Question 3a 8
Question 3b 8
Question 3c 10
Question 3d 11
Question 4 12
Question 5 14
References 15
Question 1
The sampling method that Mr. Kwok is using is Stratified Random Sampling Method. In this case study, Mr Kwok collected a random sample of 1000 flights and proportions of three routes in the sample. He divides them into different sub-groups such as satisfaction, refreshments and departure time and then selects proportionally to highlight specific subgroup within the population. The reasons why Mr Kwok used this sampling method are that the cost per observation in the survey may be reduced and it also enables to increase the accuracy at a given cost.
TABLE 1: Data Summaries of Three Routes
Route 1
Route 2
Route 3
Normal(88.532,5.07943)
Normal(97.1033,5.04488)
Normal(107.15,5.15367)
Summary Statistics
Mean
88.532
Std Dev
5.0794269
Std Err Mean
0.2271589
Upper 95% Mean
88.978306
Lower 95% Mean
88.085694
N
500
Sum
44266
Summary Statistics
Mean
97.103333
Std Dev
5.0448811
Std Err Mean
0.2912663
Upper 95% Mean
97.676525
Lower 95% Mean
96.530142
N
300
Sum
29131
Summary Statistics
Mean
107.15
Std Dev
5.1536687
Std Err Mean
0.3644194
Upper 95% Mean...

...Trajico, Maria Liticia D.
BSEd III-A2
REFLECTION
The first thing that puffs in my mind when I heard the word STATISTIC is that it was a very hard subject because it is another branch of mathematics that will make my head or brain bleed of thinking of how I will handle it. I have learned that statistic is a branch of mathematics concerned with the study of information that is expressed in numbers, for example information about the number of times something happens. As I examined on what the statement says, the phrase “number of times something happens” really caught my attention because my subconscious says “here we go again the non-stop solving, analyzing of problems” and I was right. This course of basic statistic has provided me with the analytical skills to crunch numerical data and to make inference from it. At first I thought that I will be alright all along with this subject but it seems that just some part of it maybe it is because I don’t pay much of my attention to it but I have learned many things. I have learned my lesson.
During our every session in this subject before having our midterm examination I really had hard and bad times in coping up with this subject. When we have our very first quiz I thought that I would fail it but it did not happen but after that, my next quizzes I have taken I failed. I was always feeling down when in every quiz I failed because even though I don’t like this...

...
EXAM 3
Alice Cline
PSY325: Statistics for the Behavioral and Social Sciences
Instructor Jeral Kirwan
April 7, 2014
INTRODUCTION
In 2012, the presidential election was in the spotlight as a result of power statistics when the founder of the FiveThirtyEight blog Nate Silver; prophesized the results of 50 states by using a statistical model of polling information. Nate Silver then wrote his best-selling book stressing the importance of statistical thinking (Silver 2012). His book also became famous in international regions as well. Thus media reports, statisticians in all fields of science and society remain anonymous to many people globally. At the same time, new data remains ambitious as age demands a huge statistical workforce, leaving students vulnerable to a lack of knowledge of these opportunities of study. However, it is fortunate that statistical professional societies are polished and did embrace the challenges involved. The largest professional societies in the world by the name of The American Statistical Association (ASA), has been one of the leading advocates for decades showing how important statistics are regarding science and society. This paper will illustrate and example of a statistical study of memory (Davidian, M. (2014). No-one really realizes how important memory is until theirs is compromised by either a sudden accident or a neurological disease such as Dementia or Alzheimer strikes them....

...Preliminary Observations
• The Mean of AA Fly (7.167) is lesser than TT Air (10.229). This means that the average number of hours of AA Fly is lesser than TT Air during each 24-hour period i.e. (10.229-7.167=3.062).
• The sample size of AA Fly (27) is lesser than TT Air (28). Even though AA Fly’s sample is 1 day shorter than TT Air, it does not significantly affect the output as the one day does not change much (unless there had been a market shock). However based on Central Limit Theorem, if the sample size is greater than or equal to 30 samples, the sample statistics reflect the time population parameters.
• The Median data does not show much in this case as the range (4.7 AA Fly and 6.8 TT Air) is small for both AA Fly and TT Air. This means that the mean is more applicable to be used.
• The Mode of AA Fly (7.3) is much nearer to the mean (7.167) compared to TT Air (9.2) which is much further (mean of TT Air, 10.229). This means that there is a high occurrence of AA Fly clustered around its mean.
• The Standard Deviation which compares the dispersion shows that AA Fly (1.2478) is clustered more closely compared to TT Air (1.6602).
• Since to the Standard Deviation for AA Fly is closer, the variance for AA Fly (1.557) as compared to TT Air (2.756) shows clearly the dispersion rate of both variables.
In conclusion, this could mean that TT Air has maximized their usage of aircrafts and is more efficient than AA Fly.
[Com: Good work on...

...
Final Project: Nyke Shoe Company
Barbara Greczyn
STA 201 - Principles of Statistics
Instructor Alok Dihtal
April 26, 2015
Introduction
Nyke Shoe Company has been in business for over 50 years. Over the last five years, the company has been undergoing some financial hardship due to an erratic market and an inability to understand what the consumer actually needs. In a last ditch effort to avoid bankruptcy, they have adopted a new business model which entails the development of only one shoe size. In order to achieve this goal, statistical data must be utilized and applied to make the best choice. The data used will be explained to the fullest and a conclusion will be then obtained.
Methodology
A sample group of 35 participants was gathered, 18 females and 17 males. Their heights and shoe sizes were gathered and their data was processed in three categories: shoe size, height, gender. Descriptive statistics was applied to three separate data sets, one with all participants included, one sets with just female participants, and one with just male participants. Then a two sample t-test was conducted with the assumption that there were unequal variances amongst both male and female data sets.
Results
There is a normal distribution of the data with ranges in size from size 5 to size 14 amongst the participants. With these ranges, the mean is 9.142, with a standard deviation of 2.583 and a variance of 6.670....

...Ch. 7 Pr. 1
For a population containing N=902 individuals, what code number would you assign for;
a. The first person on the list= 001
b. The fortieth person on the list= 040
c. The last person on the list= 902
Ch. 7 Pr. 13
What additional information would you want to know about the survey before you accepted the results of the study?
-Why was the study conducted? –What was the margin of error? –What was the sample size? -What sampling design was used? –What was the response rate? –What was the frame that was used? -Who paid for the survey? –From the sample that was selected, what was the population?
Ch. 7 Pr. 17
For each of the following three populations, indicate what the sampling distribution for samples of 25 would consist of:
a. Travel expense vouchers for a university in an academic year.
-The sampling distribution of a sample means is the distribution of means from all possible samples of 25 vouchers that could possibly happen.
Ch. 7 Pr.24
A random sample of 50 households as selected for a telephone survey. The key question asked was, “Do you or any member of your household own a cellular telephone with a built in camera?” Of the 50 respondents, 15 said yes and 35 said no.
a. Determine the sample proportion, p, of households with cellular telephones with built-in cameras.
P=x/n
P=15/50=0.30
-30% of the households surveyed had cell phones with cameras.
b. If the population...

...number of ways to summarise the information in data sets, also known as
descriptive statistics. It includes graphical and tabular summaries, as well as summary measures
such as means, medians and standard deviations.
Uncertainty is a key aspect of most business problems. To deal with uncertainty, we need a basic
understanding of probability. Chapter 2 covers basic rules of probability and in Chapter 3 we
discuss the important concept of probability distributions in some generality.
In Chapter 4 we discuss statistical inference (estimation), where the basic problem is to estimate
one or more characteristics of a population. Since it is too expensive to obtain the population
information, we instead select a sample from the population and then use the information in the
sample to infer the characteristics of the population.
In Chapter 5 we look at the topic of regression analysis which is used to study relationships
between variables.
In Chapter 6 we study another type of decision making called decision analysis where costs and
proﬁts are considered to be important. The problem is not whether to accept or reject a statement
but to select the best alternative from a list of several possible decisions. Usually no statistical
data are available. Decision analysis is the study of how people make decisions, particularly
when faced with imperfect information or uncertainty.
Chapter 7 deals with project management. Project management...